Telescopic hand tool

ABSTRACT

A telescopic hand tool consists of a main body, a bar and a positioning device. The bar possesses an axial hole bored axially from its one end for engaging with a telescopic bar of the main body, and a sliding groove dug around its surface, bored with a ball hole. The positioning device includes a restricting knob, a compression spring and a restricting plate. The restricting knob can slide restrictively along within the sliding groove by means of a restricting block so as to let the main body move in the bar axially. The compression spring can push elastically the restricting knob back to its original position to press on a steel ball restricted in a restricting ball hole of the main body, keeping the main body locked restrictively in the bar.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a hand tool, particularly to one that can beadjusted telescopically and kept immovably by means of a knob able tore-position automatically.

2. Description of the Prior Art

Commonly, as shown in FIG. 1, a conventional telescopic hand tool 10 iscomposed of a main body 11, a bar 12, a controlling cover 13, acompression spring 14 and a C-shaped lock washer 15. The main body 11 isprovided with plural restricting ball holes 111 bored axially withequidistance and a shallow groove 112 concaved to communicate with therestricting ball holes 111. The bar 12 is provided with a positioninghole 121 bored at its one end for a positioning ball 122 to stay on, andan annular slot 123 bored around a certain spot. The controlling cover13 is provided with a controlling groove 131 and an accommodating groove132 formed respectively on its inner wall of two opposite sides andspaced apart by a blocking projection edge 133 provided with acontrolling slope 1331 formed at its one side. The compression spring 14is mounted on the bar 12. When the length of the hand tool is to beadjusted, the controlling cover 13 has to be moved toward the C-shapedlock washer 15 fitted in the annular slot 123, keeping the controllingslope 1331 of the controlling cover 13 separated from the positioningball 122 but staying in the controlling groove 131 without beingrestricted by the restricting ball holes 111 and the shallow groove 112.Thus, the main body 11 can be moved to a desired location and positionedrestrictively while releasing the controlling cover 13 to move back toits original location, keeping the positioning ball 122 fittedrestrictively in another restricting ball hole 111 again. But, it is soinconvenient that the controlling cover 13 has to be continuouslydragged axially while adjusting the length of the main body 11.Moreover, the compression spring 14 is installed between the controllingcover 13 and the bar 12, not only relatively increasing a gap betweenthe controlling cover 13 and the bar 12 but also apt to cause thecontrolling cover 13 moving vacillatingly along the bar 12.

SUMMARY OF THE INVENTION

The objective of this invention is to offer a telescopic hand tool.

The main characteristics of the invention are a main body, a bar and apositioning device. The bar is provided with an axial hole bored axiallyfrom its one end for engaging with a telescopic bar of the main body,and a sliding groove dug around its surface, bored with a ball hole. Thepositioning device is composed of a restricting knob, a compressionspring and a restricting plate. The restricting knob can sliderestrictively along the sliding groove by means of a restricting blockso as to let the main body move in the bar axially. The compressionspring can push elastically the restricting knob back to its originalposition to press on a steel ball constrained in a restricting ball holeof the main body, keeping the main body locked restrictively in the bar.Therefore, by means of the restricting block of the restricting knobkeeping the steel ball in the restricting ball hole immovably, the mainbody is positioned precisely and stably in the bar. And, the compressionspring can elastically push the restricting knob back to its originalposition to restrict the steel ball from moving. The restricting knobcan be just operated to move right or left by a finger for adjusting thelength of the main body, conforming with requirements of humanizationand simplification.

BRIEF DESCRIPTION OF DRAWINGS

This invention is better understood by referring to the accompanyingdrawings, wherein:

FIG. 1 is a cross-sectional view of a conventional telescopic hand tool;

FIG. 2 is a perspective view of a first preferred embodiment of atelescopic hand tool in the present invention;

FIG. 3 is an exploded perspective view of the first preferred embodimentof a telescopic hand tool in the present invention;

FIG. 4 is a cross-sectional view of the first preferred embodiment of atelescopic hand tool in the present invention, showing its main bodypositioned restrictively by its bar;

FIG. 5 is a cross-sectional view of the first preferred embodiment of atelescopic hand tool in the present invention, showing the main bodyloosened by the bar to move in the bar;

FIG. 6 is a cross-sectional view of the first preferred embodiment of atelescopic hand tool in the present invention, showing how the main bodybe positioned restrictively by the bar;

FIG. 7 is a cross-sectional view of the first preferred embodiment of atelescopic hand tool in the present invention, showing how the main bodybe loosened by the bar; and

FIG. 8 is a partial exploded perspective view of a second preferredembodiment of a telescopic hand tool in the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in FIGS. 2 and 3, a first preferred embodiment of a telescopichand tool in the present invention is composed of a main body 20, a bar30 and a positioning device 40.

The main body 20 is provided with a working head 21 formed in its frontportion and a telescopic bar 22 formed in its rear portion. The workinghead 21 is provided with a ratchet set 211 for engaging with a tool. Thetelescopic bar 22 formed cylindrical is provided with plural restrictingball holes 221 bored axially with equidistance, and a shallow groove 222concaved with a depth lower than that of the restricting ball holes 221,for communicating with the restricting ball holes 221.

The bar 30 formed as an annular column is provided with an axial hole 31bored axially from its one end for engaging with the telescopic bar 22of the main body 20, a sliding groove 32 dug near the opening of theaxial hole 31 to form as a two-step ladder, and a ball hole 33 bored inthe sliding groove 32 for a steel ball 34 to fit in. The diameter of theball hole 33 is slightly larger than that of the steel ball 34, enablingthe steel ball 34 positioned restrictively in the restricting ball holes221 of the main body 20. In addition, the bar 30 is also provided with aprojection 35 planted longitudinally at two sides of the sliding groove32 respectively and a grip 36 wrapped around a portion opposite to theaxial hole 31 for a user to hold.

The positioning device 40, as shown in FIGS. 4˜6, is fixed on thesliding groove 32 of the bar 30, provided with a restricting knob 41, acompression spring 42 and a restricting plate 43. The restricting knob41 is provided with a restricting block 411 located at its bottom sideto correspond with the sliding groove 32, able to keep the restrictingknob 41 sliding along the sliding groove 32, and a push key 412 formedtriangular on its top side for a user to easily push it to keep therestricting knob 41 sliding along the sliding groove 32. The restrictingknob 41 is in addition provided with a wing 413 formed at its two curvedsides respectively, corresponding to the sliding groove 32. Thecompression spring 42 is installed in the sliding groove 32 andconstrained by the restricting block 411 while sliding the restrictingknob 41, keeping one end of the compression spring 42 contacted with thesliding groove 32 and the other end leaned on the restricting block 411,so that the restricting knob 41 can be pushed back to its originalposition by the compression spring 42 elastically. The restricting plate43 is formed as an arc-like plate to correspond with the sliding groove32 of the bar 30, provided with an elongate opening 431 shapedrectangular cut in its central portion to correspond with the slidinggroove 32 for the restricting knob 41 to fit through to enable therestricting plate 43 fixed at two edges of the sliding groove 32,keeping the push key 412 exposed outside. The restricting plate 43 isadditionally provided with a restricting portion 432 formed at two sidesof the elongate opening 431 respectively, able to press on the wings 413of the restricting knob 41 to let the restricting knob 41 slide alongthe sliding groove 32. In addition, there is a positioning hole 433bored at two sides of the restricting plate 43 respectively forcorrespondingly fitting with the projection 35. Finally, the restrictingplate 43 is restrictively fixed on the edge of the sliding groove 32.Though the restricting knob 41 and the restricting plate 43 arepreferably made of metal, they can also be made of plastics easilyformed into a variety of shapes.

In assembly, as shown in FIGS. 3 and 4, the steel ball 34 is first putin the ball hole 33 of the sliding groove 32 of the bar 30 and therestricting block 411 of the restricting knob 41 is fitted in thesliding groove 32 to enable the restricting knob 41 to slide along thesliding groove 32. When the main body 20 is moved to a desired position,the steel ball 34 is to sink in one of the restricting ball holes 221 tolet the restricting knob 41 move to the top of the steel ball 34,keeping the steel ball 34 pressed by the restricting block 411 to befitted in one of the restricting ball hole 221 to make the main body 20positioned restrictively in the bar 30. Next, install the compressionspring 42 between the sliding groove 32 and the restricting block 411for elastically pushing the restricting knob 41 back to its originalposition after having been pushed away. Then, put the restricting plate43 on the sliding groove 32 and keep the positioning holes 433 engagedwith the projections 35, so that the restricting plate 43 is fixed abovethe sliding groove 32 of the bar 30. Spontaneously, the wings 413 of therestricting knob 41 are pressed by the restricting portion 432 of therestricting plate 43 to constrain the restricting knob 41 to slide alongwithin the sliding groove 32.

In using, as shown in FIGS. 5˜7, the knob 412 of the restricting knob 41has to be pushed to keep the restricting block 411 moved away from thesteel ball 34, enabling the steel ball 34 released from the restrictingball hole 221 to move up in the shallow groove 222, so that the mainbody 20 can freely move to and fro in the bar 30. As the main body 20 isadjusted to another new position, the steel ball 34 is to spontaneouslysink in one of the restricting ball holes 221 again. Then, as shown inFIGS. 4 and 6, the restricting knob 41 is allowed to move backelastically by the compression spring 42 to keep the steel ball 34pressed by the restricting block 411, correspondingly positioning thesteel ball 34 in that one of the restricting ball holes 221 andrestricting the main body 20 from moving in the bar 30.

As shown in FIG. 8, a second preferred embodiment of a telescopic handtool in the present invention has the same components as the firstembodiment does except those described below. There are twofemale-threaded holes 37 bored at two sides of the sliding groove 32respectively. The restricting plate 43 is provided with two throughholes 434 bored at its two sides respectively, corresponding to thefemale-threaded holes 37 for screws 38 to pass through to screw fixedlywith the female-threaded holes 37, keeping the restricting plate 43fixed on the sliding groove 32 of the bar 30. In addition, an arrow mark435 is printed on an outer surface of the restricting plate 43 toindicate the direction for a user to operate the restricting knob 41.

The advantages of the invention are abbreviated below as can be seenfrom the foresaid description. By means of the restricting block 411 ofthe restricting knob 41 keeping the steel ball 34 in the restrictingball hole 221 immovably, the main body 20 is positioned precisely andstably in the bar 30. And, the compression spring 42 can elasticallypush the restricting knob 41 back to its original position to restrictthe steel ball 34 from moving easily. The restricting knob 41 can bejust operated to move right or left by a finger for adjusting the lengthof the main body 20, conforming with requirements of humanization andsimplification.

While the preferred embodiment of the invention has been describedabove, it will be recognized and understood that various modificationsmay be made therein and the appended claims are intended to cover allsuch modifications that may fall within the spirit and scope of theinvention.

1. A telescopic hand tool comprising: a main body provided with aworking head formed in its front portion for engaging with a tool and atelescopic bar formed in its rear portion, said telescopic bar providedwith plural restricting ball holes bored axially and a shallow grooveconcaved to communicate with said restricting ball holes, saidrestricting ball holes having a depth deeper than that of saidrestricting ball holes; a bar provided with an axial hole bored axiallyfrom its one end for engaging with said telescopic bar of said main bodyand a sliding groove dug near an opening of said axial hole 31, saidsliding groove bored with a ball hole for fitting with a steel ball thatis correspondingly to be fitted in said restricting ball hole of saidmain body; and a positioning device fixed on, said sliding groove ofsaid bar and provided with a restricting knob, a compression spring anda restricting plate, said restricting knob provided with a restrictingblock located at its bottom side to correspond with said sliding grooveso that said restricting knob is able to slide along said sliding grooveand press said steel ball to be positioned in one of said restrictingball holes, and a push key formed on an top side of said restrictingknob for a user to easily push it to keep said restricting knob slidingalong within said sliding groove, said restricting knob also providedwith a wing formed at its two curved sides respectively to correspond tosaid sliding groove, said compression spring installed between saidrestricting block and said sliding groove and able to push elasticallysaid restricting knob to move back to its original position after pushedaway, said restricting plate provided with an elongate opening cut inits central portion to correspond with said sliding groove for fittingwith said restricting knob so as to keep said restricting plate fixed attwo edges of said sliding groove, and a restricting portion formed attwo sides of said elongate opening respectively for pressing on saidwings of said restricting knob to let said restricting knob slide alongwithin said sliding groove.
 2. A telescopic hand tool as claimed inclaim 1, wherein said sliding groove is formed as a two-step ladder forsaid wings of said restricting knob to attach, said wings furtherpressed by said restricting portion of said restricting plate to keepsaid restricting knob sliding restrictively along said sliding groove.3. A telescopic hand tool as claimed in claim 1, wherein saidcompression spring is installed in said sliding groove and constrainedby said restricting block, keeping one end of said compression springcontacted with said sliding groove and the other one leaned on saidrestricting block so that said restricting knob can be pushed back toits original position by said compression spring elastically.
 4. Atelescopic hand tool as claimed in claim 1, wherein said bar is providedwith a projection planted longitudinally at two sides of said slidinggroove respectively for fitting with a restricting hole boredcorrespondingly at two sides of said restricting plate to keep saidrestricting plate fixed on the edge of said sliding groove of said bar.5. A telescopic hand tool as claimed in claim 1, wherein said slidinggroove of said bar is provided with two female-threaded holes bored atits two sides respectively, said restricting plate provided with twothrough holes bored at its two sides respectively to correspond to saidfemale-threaded holes for screws to pass through to screw fixedly withsaid female-threaded holes, keeping said restricting plate fixed on theedge of said sliding groove of said bar.
 6. A telescopic hand tool asclaimed in claim 1, wherein said bar is provided with a grip wrappedaround some of its surface.
 7. A telescopic hand tool as claimed inclaim 1, wherein said restricting knob and said restricting plate aremade of metal.
 8. A telescopic hand tool as claimed in claim 1, whereinsaid restricting knob and said restricting plate are made of plastics.9. A telescopic hand tool as claimed in claim 1, wherein saidrestricting plate is provided with an arrow mark printed on its outersurface.